This invention relates generally to conveyor-type article transport mechanisms and is particularly directed to an arrangement for changing the spacing between adjacent articles as they are linearly displaced on a conveyor-type transport mechanism without interrupting the transport of the articles.
Automatic procedures and apparatus are increasingly being used in manufacturing for sequentially displacing a plurality of articles of manufacture to various work stations. At each work station the articles undergo another step in the manufacturing process which typically involves the manipulation and processing of the article by automatic handling apparatus. In one common approach, each article is positioned upon and displaced by a conveyor-like transport mechansim to various work stations whereat each article is, in turn, manipulated such as by a robotic grasping arm with pincers for positioning or orienting the article as desired. This procedure is particulary adapted for the high speed, automatic handling of large numbers of electronic/electrical components which undergo various fabrication, testing and circuit insertion procedures at several work stations.
Where the articles being processed, such as in the case of electronic/electrical components, are small in size, special consideration must be given to the design and operation of th transport system used to convey the articles between the various work stations. For example, sufficient inter-article space must be provided to allow the article manipulating apparatus to grasp one article without disturbing the position and orientation of adjacent articles. In addition, sufficient inter-article space frequently must be provided to allow an article to undergo a manufacturing process step, e.g., testing, re-orientation, etc., while positioned adjacent to the conveyor-like transport mechanism without interrupting the displacement of the transport mechanism or disturbing immediately adjacent articles. However, the inter-article spacing required for processing and manipulating the articles is generally greater than the optimum spacing for deposit of the articles on the conveyor-like transport mechanism. For example, in order to minimize space and the time required for deposit of the articles upon the conveyor-like transport mechanism, a large number of articles should simultaneously be positioned upon the transport mechanism in a closely spaced arrangement. However, as described above, this close inter-article spacing may not allow for the aforementioned automatic manipulation of the articles such as by a robotic grasping arm with pincers.
The present invention addresses the aforementioned article spacing problem in a conveyor-like transport system by providing for the proportional displacement of first and second adjacent walking beams between which articles are transferred to allow the articles to be linearly displaced with a first inter-article spacing on one of the walking beams and with a second, different inter-article spacing on the other walking beam.